All Free Biology MCQs with Answers

• A. Haploid, single stranded, coiled
• B. Diploid, double stranded, coiled
• C. Haploid, double stranded, coiled
• D. Diploid, single stranded, coiled

Explanation: Bacterial DNA is characterized by being a single, circular, double stranded molecule that is tightly coiled to fit within the cell.

• A. Cellulose
• B. Chitin
• C. Murein
• D. Pectin

Explanation: Option C is correct.The prokaryotic cell wall is composed of murein, also known as peptidoglycan.

• A. Valine acid
• B. Alamine acid
• C. Arginine acid
• D. Methionine acid

Explanation: Sickle cell anemia results from the single amino acid substitution of valine for glutamic acid in the beta-chain owing to a nucleotide…

• A. Amino groups on the amino acids
• B. R- groups on the amino acids·
• C. Peptide bonds
• D. Amino acids sequences within protein molecules

Explanation: Diversity refers to different types of proteins.

• A. Hydrogen groups of adjacent amino acids
• B. Functional group of the amino acids
• C. Carboxyl group and amino group
• D. Functional group and hydrogen group of adjacent amino acid

Explanation: Carboxyl or COOH- a group of one amino acid and Amine or NH3+ of another Amino acid are responsible for forming peptide bonds.

• A. Four oxygen molecules
• B. Three oxygen molecules
• C. Two oxygen molecules
• D. One oxygen molecule

Explanation: Myoglobin is a protein found in muscle tissues with a tertiary structure comprising a single polypeptide chain.

• A. Hairs
• B. Haemoglobin
• C. Muscle cells
• D. Nails

Explanation: Hemoglobin is indeed an example of a globular protein. It's a protein found in red blood cells that helps transport oxygen throughout the…

• A. Renin
• B. Insulin
• C. Caesin
• D. Prolactin

Explanation: Casein is a type of protein that is naturally present in milk. It makes up about 80% of the total protein content in cow's milk.

• A. Proline
• B. Glutamine
• C. Valine
• D. Glycine

Explanation: Option C is correct. In sickle cell anemia, glutamic acid in the hemoglobin molecule is replaced by valine.

• A. R-group
• B. Amino group
• C. Carboxyl group
• D. Hydrogen of alpha carbon

Explanation: Option A is correct.Amino acids mainly differ from each other by the difference in their R-group.

• A. Coordinate bond
• B. Covalent bond
• C. Hydrogen bond
• D. Ionic bond

Explanation: Hydrogen bonds play a crucial role in determining the secondary structure of proteins.

• A. Mechanical
• B. Chemical
• C. Photoreceptors
• D. Georeceptors

Explanation: Receptors sensitive to smell are chemoreceptors, specifically olfactory receptors.

• A. Mechanical
• B. Chemical
• C. Photoreceptors

Explanation: Chemical receptors are sensitive to chemicals and they help differentiate and recognize taste,smell and detect changes in O2 ,CO2 and Ph.

• A. Temperature
• B. Pain
• C. Pressure
• D. Touch

Explanation: Meissner corpuscles are integral to the human sensory system, specifically involved in detecting light touch.

• A. Gustation
• B. Tactician
• C. Nociception
• D. Olfaction

Explanation: The correct answer is Gustation. This term is used to describe the process of detecting taste through taste buds located on the tongue…

• A. Walls of blood vessels
• B. Tongue
• C. Skin
• D. Ear

Explanation: Baroreceptors are primarily found in the walls of blood vessels. They are specialized sensory receptors that detect changes in blood…

• A. Sole
• B. Lips
• C. Back of the hand
• D. Palm

Explanation: Tactition receptors are abundant in the human sole, which is the bottom part of the foot.

• A. Rat
• B. Dog
• C. Goose
• D. Chimpanzee

Explanation: Ivan Pavlov, a Russian physiologist, used dogs as experimental animals to study conditioned reflexes.

• A. Sensory nerve
• B. Motor nerve
• C. Autonomic response
• D. Sympathetic nerve

Explanation: A is correct because in a reflex action, a sensory nerve is responsible for detecting a stimulus (such as heat, pain, etc.) and…

• A. Thymine
• B. Adonine
• C. Guanine
• D. Cytosine

Explanation: DNA contains the following bases: adenine, guanine, cytosine, and thymine.